Flooding Rains Repeatedly Drenched The Southeast This May

It's been unrelentingly stormy in the southeastern United States over the past month. It feels like the weather has been stuck on repeat for a while now. You could copy and paste the weather report from four weeks ago and reuse it each week just by changing out some maps and dates. The stagnant patterns have lead to repeated thunderstorms moving over the same areas for days at a time. That persistent rain is coming at a cost. The month will end as the wettest on record for some and it’ll leave behind an awful legacy for others.

This past May was Asheville, North Carolina’s wettest month on record. The city’s airport saw 13.97” of rain through the evening of May 30, 2018, breaking the all-time monthly rainfall record of 13.69” set there back in July 2013. Records at the Asheville Airport go back to 1946. A nearby weather station in Asheville has records going all the way back to 1897 and the greatest monthly rainfall recorded there was 13.75” in August 1940.

The recent heavy rains in North Carolina left the ground soaked and the situation was only exacerbated by the passing of Subtropical Storm Alberto earlier this week. Heavy rain over the past few days led to a landslide that briefly compromised the integrity of a dam on Lake Tahoma, located about 30 miles northeast of Asheville. A landslide in the town of Boone swept away a house, killing both people inside.

North Carolina isn’t the only place seeing flooding from record rainfall. Ellicott City, Maryland, near Baltimore, recently dealt with devastating flooding that tore through the town on May 27. A series of thunderstorms dropped nearly a foot of rain on the town and nearby areas in a short period of time that afternoon. The water funneled into historic Ellicott City—notoriously located directly above the confluence of several waterways—and the city briefly became part of the river itself. The flash flood disaster was caused as much by excessive rainfall as it was the fault of development in a vulnerable spot and nearby development leading to excess runoff.

Flash flooding also hit Charlottesville, Virginia, hard on the evening of May 30. A stationary thunderstorm over Charlottesville and surrounding towns dropped up to 10” of rain in a couple of hours. The flash flooding up and down the areas along U.S. Highway 29 was so bad that the National Weather Service issued a flash flood emergency for the area, calling it a “particularly dangerous situation.”

Southeastern Florida has also seen quite a bit of rain this month. Much of the state’s southeastern coast seen more than a foot-and-a-half of rain since the first of the month. An observing station at Fort Lauderdale Beach saw 17.83” of rain, making this the station’s wettest May on record. The rain broke the same record up the coast in Stuart, Florida, where 22.20” has fallen so far in the small town near Port St. Lucie.

Why have we been mired in this rainy pattern? The jet stream retreated far north into Canada a few weeks ago, leaving us at the mercy of smaller-scale features moving across the United States. The driving force for much of our weather has been the Bermuda High, a large high-pressure system over the western Atlantic Ocean, pushing moist, tropical air into the southeast. This allowed thunderstorms to wring-out the tropical moisture and produce excessive rainfall wherever they set up for a long period of time.

The pattern will start to change a bit as we head into June. The Bermuda High will break down going into the first week of the month, allowing more variable weather to take hold for the next two weeks. That being said, it won’t take much of a heavy downpour to create more flooding concerns over areas where the soil is already saturated.

I'm a writer who focuses on the weather and everything related to it, from sprawling storms that span continents to the interpersonal issues we encounter when trying to communicate hazards to the public. I graduated from the University of South Alabama in 2014 with a degree ...